1. Field of the Invention
The present invention relates generally to displaying graphics on an electronic display screen and, more particularly, to preparing graphics for display on an electronic display screen of an electronic device or portable computer system.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
An electronic display screen for an electronic device often displays a new frame of pixels each time the screen refreshes. Each successive frame of pixels may be stored in a portion of memory known as a framebuffer, which holds data corresponding to each pixel of the frame. Before reaching a target framebuffer, each frame is typically processed using both hardware and software.
Often, a stage of frame processing will move forward when the screen refreshes and sends a vertical blanking (VBL) interrupt command, known as a VBL heartbeat. By synchronizing to the VBL heartbeat, frame processing maintains an orderly progression toward a target framebuffer. However, if a particular stage of frame processing takes too long, a VBL heartbeat may occur before the frame is ready to move to the next stage of processing, and the frame may thus be delayed or discarded. Additionally, hardware-based processing may avoid processing a frame while a target framebuffer is in use.
An electronic device may employ multiple layers of frames of pixels, which may be accumulated into a single layer for display on the screen. At least one unique framebuffer may correspond to each layer. Since each frame of each layer may require frame processing prior to accumulation, a failure during frame processing may be magnified, as more than one layer may be affected.